Previously, Button::set_icon required moving the bitmap into the
button, preventing the same bitmap from being used by multiple
buttons at once. While this works for buttons that are created once,
any button that is dynamically added would require the same bitmap to
be loaded every single time. In addition to being ineffecient, this
also makes error checking more difficult.
With this change, a bitmap can be loaded once, and passed to multiple
buttons.
When a Button has a menu, the AbstractButton behaviour will now not
be used in the mousemove_event. This was already the case for
mousedown_event.
Why only sometimes?
Normally the presence of the menu prevents mousemove_events from being
delivered to the button. But the menu doesn't spawn immediately. So
sometimes mousemove events got through to the AbstractButton after the
menu was told to spawn but before it appeared. This caused the
m_being_pressed field of AbstractButton to be set to true. But there
was never a mouseup_event because the menu got those instead.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
When a button has a menu, it opens the menu on mousedown and the
menu gains input focus immediately. While the menu is open, the
button is painted in a pressed state.
